Evaluate the following expression when $x = 5$ and $y = 9$. $3$ $x$ $ + 6$ $y$ $ + 7$
Solution: Substitute $5$ for ${x}$ and $9$ for ${y}$ $ = 3{(5)} + 6{(9)} + 7 $ $ = 15 + 54 + 7 $ $ = 76$